title: Differences in candidate gene association between European ancestry and African American asthmatic children.
abstract: BACKGROUND
  Candidate gene case-control studies have identified several single nucleotide polymorphisms (SNPs) that are associated with asthma susceptibility. Most of these studies have been restricted to evaluations of specific SNPs within a single gene and within populations from European ancestry. Recently, there is increasing interest in understanding racial differences in genetic risk associated with childhood asthma. Our aim was to compare association patterns of asthma candidate genes between children of European and African ancestry.
  
  
  RESULTS
  Using a custom-designed Illumina SNP array, we genotyped 1,485 children within the Greater Cincinnati Pediatric Clinic Repository and Cincinnati Genomic Control Cohort for 259 SNPs in 28 genes and evaluated their associations with asthma. We identified 14 SNPs located in 6 genes that were significantly associated (p-values <0.05) with childhood asthma in African Americans. Among Caucasians, 13 SNPs in 5 genes were associated with childhood asthma. Two SNPs in IL4 were associated with asthma in both races (p-values <0.05). Gene-gene interaction studies identified race specific sets of genes that best discriminate between asthmatic children and non-allergic controls.
  
  
  CONCLUSIONS
  We identified IL4 as having a role in asthma susceptibility in both African American and Caucasian children. However, while IL4 SNPs were associated with asthma in asthmatic children with European and African ancestry, the relative contributions of the most replicated asthma-associated SNPs varied by ancestry. These data provides valuable insights into the pathways that may predispose to asthma in individuals with European vs. African ancestry.
authors.affiliation: Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, United States of America.
authors.forename: Tesfaye M
authors.initials: TM
authors.lastname: Baye
authors.forename: Melinda
authors.initials: M
authors.lastname: Butsch Kovacic
authors.forename: Jocelyn M
authors.initials: JM
authors.lastname: Biagini Myers
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Martin
authors.forename: Mark
authors.initials: M
authors.lastname: Lindsey
authors.forename: Tia L
authors.initials: TL
authors.lastname: Patterson
authors.forename: Hua
authors.initials: H
authors.lastname: He
authors.forename: Mark B
authors.initials: MB
authors.lastname: Ericksen
authors.forename: Jayanta
authors.initials: J
authors.lastname: Gupta
authors.forename: Anna M
authors.initials: AM
authors.lastname: Tsoras
authors.forename: Andrew
authors.initials: A
authors.lastname: Lindsley
authors.forename: Marc E
authors.initials: ME
authors.lastname: Rothenberg
authors.forename: Marsha
authors.initials: M
authors.lastname: Wills-Karp
authors.forename: N Tony
authors.initials: NT
authors.lastname: Eissa
authors.forename: Larry
authors.initials: L
authors.lastname: Borish
authors.forename: Gurjit K
authors.initials: GK
authors.lastname: Khurana Hershey
mesh_terms: D000293:Adolescent; D001741:Black or African American / Q000235:genetics*; D001249:Asthma / Q000208:ethnology* / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies / Q000706:statistics & numerical data; D020022:Genetic Predisposition to Disease / Q000208:ethnology; D005838:Genotype; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D044465:White People / Q000235:genetics*